Method for Sensing Proximity by Electronic Device and Electronic Device Therefor

1. A method for sensing proximity by an electronic device, the method comprising: acquiring a phase difference regarding a corresponding subject of an image acquired through a lens of the electronic device by operating a phase-difference autofocus sensor; determining that the corresponding subject is proximate to the electronic device when the confirmed phase difference is larger than a designated first reference value; after determining that the corresponding subject is proximate to the electronic device, maintaining the lens in a reference position; determining that the corresponding subject is spaced away from the electronic device when the acquired phase difference decreases smaller than a designated second reference value; and performing a predetermined operation in response to determining that the corresponding subject is spaced away from the electronic device.

2. The method of claim 1 , further comprising: turning on the touch screen when it is determined that the corresponding subject is spaced away from the electronic device.

3. The method of claim 2 , further comprising: executing a calling mode of the electronic device according to user manipulation; and operating the phase-difference autofocus sensor at a predetermined period when the calling mode is executed.

4. The method of claim 1 , wherein the designated first reference value is a phase difference regarding a designated reference subject sensed by the phase-difference autofocus sensor at a designated first distance value, and wherein the designated second reference value is a phase difference regarding the reference subject sensed by the phase-difference autofocus sensor at a designated second distance value.

5. The method of claim 1 , further comprising operating the phase-difference autofocus sensor at a designated period.

6. An electronic device comprising: a touch screen; a lens configured to acquire an image of a subject; a phase-difference autofocus sensor configured to detect a phase difference regarding the subject; and a controller configured to: operate the phase-difference autofocus sensor, detect a phase difference regarding a corresponding subject of the image acquired through the lens, determine that the corresponding subject is proximate to the electronic device when the detected phase difference is larger than a designated first reference value, maintain the lens in a reference position after determining that the corresponding subject is proximate to the electronic device, determine that the corresponding subject is spaced away from the electronic device when the detected phase difference decreases smaller than a designated second reference value, and perform a predetermined operation in response to determining that the corresponding subject is spaced away from the electronic device.

7. The electronic device of claim 6 , wherein the controller is further configured to turn on the touch screen when it is determined that the corresponding subject is spaced away.

8. The electronic device of claim 7 , wherein the electronic device further comprises an input device for receiving inputted user manipulation, and wherein the controller is further configured to: execute a calling mode according to user manipulation inputted through the input device, and operate the phase-difference autofocus sensor at a designated period when the calling mode is executed.

9. The electronic device of claim 7 , wherein the touch screen is turned off to prevent the subject from unintentionally pressing a button of the touch-screen.

10. The electronic device of claim 6 , wherein the designated first reference value is a phase difference regarding a designated reference subject sensed by the phase-difference autofocus sensor at a designated first distance value, and wherein the designated second reference value is a phase difference regarding the designated reference subject sensed by the phase-difference autofocus sensor at a designated second distance value.